I recently shot some rolls with an older similar format Kodak- a #3. It was pretty simple to adapt 120 to work. A couple of spare 120 donor spools to cut up for adapters, a short piece of aluminum tubing from a hobby shop and a small rectangle of styrene for an advancing paddle to fit in the slot of the end of a spool. Some Cyanoacrylate glue held the bits together. To keep the film flat I used some basswood from the hobby shop but you could easily use some plastic from the recycle bin. I used a removable glue (rubber cement) to hold the plastic when reducing the opening, sand the plastic to create a tooth for the glue to take. Some gaffers tape to secure it as well. It should pop off easily and leave no trace.